Water Turbidity

AUS-TSR-LVG-WTU General Moderate confidence

Benchmark Value

No specific value — see range
Range: 15 to 20 NTU
Thresholds: Lower: 15, Upper: 20
Optimal Range: 15 to 20
Direction: Lower is desirable ↓
Form: OptimalRange

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context. The scoring engine uses 13 benchmarks together — the OptimalRange form drives the primary score, while 12 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary OptimalRange Guard UpperThreshold Guard MinimumOnly Guard OptimalRange Guard Point Guard OptimalRange Guard UpperThreshold Guard MaximumOnly Guard LowerThreshold Guard OptimalRange Guard UpperThreshold Guard Point Guard

Evidence & Context

Once baseflow turbidity consistently exceeds 15–20 NTU, significant negative impacts on a range of aquatic life and ecosystem functions are highly probable.

Metric Definition:

Water turbidity ranges in NTU indicating ecological health categories and associated risk levels in tropical grazing catchments during baseflow.

Benchmark Definition:

Threshold turbidity range indicating onset of significant ecological harm in tropical grazing catchments.

Justification:

Scientific evidence links turbidity levels above 15 NTU to reduced fish growth and above 40 NTU to severe ecosystem degradation.

Sources (1)

Preview of Assessing Water Quality - Secondary Education Years 9 to 12 - Upper Murrumbidgee Waterwatch, accessed August 12, 2025,
Assessing Water Quality - Secondary Education Years 9 to 12 - Upper Murrumbidgee Waterwatch, accessed August 12, 2025, Journal

Assessing water quality - ACT Waterwatch

View Source

Supporting Sources (22)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed August 2, 2025,
(PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed August 2, 2025,
Contextual Support

Requirements for graziers | Environment, land and water ..., accessed July 19, 2025,

View Source
Preview of (PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed July 19, 2025,
(PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed July 19, 2025,
Contextual Support Journal

Climate change and its implications for Australia´s freshwater fish - CSIRO Publishing, accessed July 19, 2025,

View Source
Preview of A Compendium of Ecological Information on Australia's Northern Tropical Rivers - Report 5 - Water quality - DCCEEW, accessed August 1, 2025,
A Compendium of Ecological Information on Australia's Northern Tropical Rivers - Report 5 - Water quality - DCCEEW, accessed August 1, 2025,
Contextual Support Journal

Threshold Indicator Taxa ANalysis and change points (dots) for the ...

View Source
Preview of A meta-analytical review of turbidity effects on fish mobility - ResearchGate, accessed July 24, 2025
A meta-analytical review of turbidity effects on fish mobility - ResearchGate, accessed July 24, 2025
Contextual Support Journal

A meta-analytical review of turbidity effects on fish mobility - ResearchGate, accessed July 19, 2025,

View Source
Preview of Backgrounder: Impact of land runoff | AIMS - The Australian Institute of Marine Science, accessed May 11, 2025,
Backgrounder: Impact of land runoff | AIMS - The Australian Institute of Marine Science, accessed May 11, 2025,
Contextual Support Government

Backgrounder: Impact of land runoff | AIMS, accessed July 19, 2025,

View Source
Preview of Do regenerative grazing management practices improve vegetation and soil health in grazed rangelands? Preliminary insights from a space-for-time study in the Great Barrier Reef catchments, Australia - ResearchGate, accessed July 19, 2025,
Do regenerative grazing management practices improve vegetation and soil health in grazed rangelands? Preliminary insights from a space-for-time study in the Great Barrier Reef catchments, Australia - ResearchGate, accessed July 19, 2025,
Contextual Support Journal

Do regenerative grazing management practices improve vegetation and soil health in grazed rangelands? Preliminary insights from a space-for-time study in the Great Barrier Reef catchments, Australia - ResearchGate, accessed July 17, 2025,

View Source
Preview of Effect of reduced grazing pressure on sediment and nutrient yields in savanna rangeland streams draining to the Great Barrier Reef - CSIRO Research Publications Repository
Effect of reduced grazing pressure on sediment and nutrient yields in savanna rangeland streams draining to the Great Barrier Reef - CSIRO Research Publications Repository
Direct Evidence Journal

Hillslope gully erosion in savanna rangelands tributary to the Great ..., accessed July 19, 2025,

View Source
Preview of Effect of reduced grazing pressure on sediment and nutrient yields in savanna rangeland streams draining to the Great Barrier Reef - ResearchOnline@JCU, accessed July 19, 2025,
Effect of reduced grazing pressure on sediment and nutrient yields in savanna rangeland streams draining to the Great Barrier Reef - ResearchOnline@JCU, accessed July 19, 2025,
Direct Evidence Journal

Effect of reduced grazing pressure on sediment and nutrient yields in savanna rangeland streams draining to the Great Barrier Reef - ResearchOnline@JCU, accessed July 19, 2025,

View Source
Preview of Grazing Best Practice
Grazing Best Practice
Contextual Support GreyLiterature

Grazing water quality risk framework 2017-2022 - Reef 2050 Water ..., accessed July 19, 2025,

View Source
Preview of Impacts of improved grazing land management on sediment yields, Part 1: Hillslope processes - ResearchGate, accessed July 19, 2025,
Impacts of improved grazing land management on sediment yields, Part 1: Hillslope processes - ResearchGate, accessed July 19, 2025,
Contextual Support Journal

Impacts of improved grazing land management on sediment yields, Part 1: Hillslope processes - ResearchGate, accessed July 19, 2025,

View Source
Preview of Improved Methods for Correlating Turbidity and Suspended Solids for Monitoring - CLU-IN
Improved Methods for Correlating Turbidity and Suspended Solids for Monitoring - CLU-IN
Methodology Source Journal

Water-quality and ecosystem impacts of recreation in streams: Monitoring and management, accessed July 19, 2025,

View Source
Preview of Land management for graziers | Business Queensland, accessed August 8, 2025
Land management for graziers | Business Queensland, accessed August 8, 2025
Contextual Support Government

Reducing the impacts of grazing on water quality - EPA Victoria, accessed July 19, 2025,

View Source
Preview of Mutual relationships of suspended sediment, turbidity and visual clarity in New Zealand rivers - PIAHS, accessed July 19, 2025,
Mutual relationships of suspended sediment, turbidity and visual clarity in New Zealand rivers - PIAHS, accessed July 19, 2025,
Contextual Support Journal

Mutual relationships of suspended sediment, turbidity and visual clarity in New Zealand rivers - PIAHS, accessed July 19, 2025,

View Source
Preview of Natural water systems | Australia state of the environment 2021, accessed July 16, 2025,
Natural water systems | Australia state of the environment 2021, accessed July 16, 2025,
Contextual Support Government

Characterising the relationship between water quality and water quantity, accessed July 19, 2025,

View Source
Preview of Reducing the impacts of grazing on water quality - EPA Victoria, accessed August 8, 2025
Reducing the impacts of grazing on water quality - EPA Victoria, accessed August 8, 2025
Contextual Support Journal

Generic document, accessed July 19, 2025,

View Source
Preview of Total-Suspended-Solids-from-Turbidity-Tech-Note.pdf - In-Situ, accessed July 19, 2025,
Total-Suspended-Solids-from-Turbidity-Tech-Note.pdf - In-Situ, accessed July 19, 2025,
Methodology Source Journal

Total-Suspended-Solids-from-Turbidity-Tech-Note.pdf - In-Situ, accessed July 19, 2025,

View Source
Preview of Turbidity-based erosion estimation in a catchment in South Australia - ResearchGate, accessed July 19, 2025,
Turbidity-based erosion estimation in a catchment in South Australia - ResearchGate, accessed July 19, 2025,
Methodology Source Journal

Turbidity-based erosion estimation in a catchment in South Australia - ResearchGate, accessed July 19, 2025,

View Source
Preview of Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed August 11, 2025,
Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed August 11, 2025,
Contextual Support Journal

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000) - Tuvalu Environment Data Portal, accessed July 19, 2025,

View Source
Preview of Water quality for livestock, accessed July 29, 2025,
Water quality for livestock, accessed July 29, 2025,
Contextual Support Journal

Top 10 Strategies for Efficient Water Management on Your Farm - SONIC Natural Farming, accessed July 19, 2025,

View Source
Preview of Water Quality Guidelines for the Great Barrier Reef Marine Park.
Water Quality Guidelines for the Great Barrier Reef Marine Park.
Direct Evidence Journal

Impact of Rainfall on Turbidity and Suspended Sediment Load at Five Sites on the Murray River Between Albury and Swan Hill and Possible Relationships to Catchment Attributes D.A Post and A.J. Jakeman - MSSANZ, accessed July 19, 2025,

View Source
Preview of Water quality of surface water environments - NSW Government Water, accessed August 1, 2025,
Water quality of surface water environments - NSW Government Water, accessed August 1, 2025,
Contextual Support Government

National Guidelines for Water Quality | Department of Natural ...

View Source
Preview of Water-quality and ecosystem impacts of recreation in streams: Monitoring and management, accessed July 22, 2025
Water-quality and ecosystem impacts of recreation in streams: Monitoring and management, accessed July 22, 2025
Contextual Support Journal

Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed July 19, 2025,

View Source

Context

  • Region Australia
  • Biome Tropical & Subtropical Rainforests
  • Land Use Livestock Grazing & Pasture
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 2
  • Effective From 25 Mar 2026

Notes

Turbidity levels above 15 NTU indicate significant negative impacts; above 40 NTU indicates severely degraded state.

Related Benchmarks

Other benchmarks in the AUS-TSR-LVG-WTU family.

5 NTU Moderate
Livestock Grazing & Pasture · Pristine Reference
Point Active v1
— NTU Moderate
Livestock Grazing & Pasture · Pristine Reference
OptimalRange Superseded v1